Field of the Invention
The present invention relates to wireless communication, and more particularly, to a service discovery method of a terminal.
Related Art
An institute of electrical and electronics engineers (IEEE) 802.11u task group (TG) serves to develop a standard for an interworking service with an external network through a 802.11 wireless local area network (WLAN). That is, the 802.11u proposes a protocol capable of informing in advance whether a specific external network service network can be connected through one given WLAN.
In the existing IEEE 802.11 standard, a variety of information is required in order for a station (STA) to perform an authentication procedure. The information may include network information for performing authentication, credential information of heterogeneous networks, and information indicating which protocol will be applied when an application currently being executed blocks another application or a TCP port.
However, in the IEEE 802.11u standard, a new protocol is proposed to perform a complex authentication procedure at a faster speed between heterogeneous networks.
In the protocol proposed in the IEEE 802.11u, a new network discovery and selection method may be performed in a media access control (MAC) layer. In the network discovery and selection method newly proposed in the IEEE 802.11u, a access point (AP) transmits a variety of information, that is, information on its network type (e.g., free, fee-based, or private network, etc.), roaming consortium information, place information, etc.) to a terminal before a station (STA) is associated with the AP, so that the STA acquires network-related information before the authentication.
For example, in the IEEE 802.11u, since information on a service which can be provided by an AP to an STA is provided to the STA in advance through a generic advertisement service (GAS) protocol before the STA is connected to a network, information on the network can be acquired before the STA and the AP are associated.